Solution Precursor Plasma-Sprayed (SPSS) HAp/Titania Coating for Biomedical Applications—Fretting Damage Analysis

Solution precursor plasma spraying (SPPS) is a new deposition technique to obtain bioactive coatings onto metallic implants for orthopedic and dental applications. This method employs powders with sizes on the micron and submicronic scale in the form of a solution. It offers several advantages over other spray processes, such as resolving the problems of particle agglomeration and sedimentation and providing better control over the morphology and chemistry of the coating. It is essential to assess the durability of the coatings, and the current work is focused on this direction. The present investigation reports the fretting wear characteristics of solution precursor plasma sprayed hydroxyapatite (HAp)/titania on a titanium substrate with a weight percentage of 50:50 which is one prime requirement for implant applications. Fretting experiments were carried out at different contact stresses and at a constant displacement amplitude in an unlubricated and lubricated environment in a laboratory room to understand better the micro-mechanisms involved in fretting wear associated with the coating when it is used for an orthopedic application. The porosity and the hardness values of the SPPS coating are higher than the suspension plasma sprayed (SPS) coated HAp/titania coating. The wear test demonstrated variation in fretting behavior as the friction logs change from gross slip to partial slip condition in the case of the coated sample as load increases. Wear debris collected from the fretting wear test was observed to be in different shapes and within 10 microns. Optical and scanning electron microscopes examine the fretting damage and find the dominant wear mechanism.